Provider parsing errors messages are not useful

[foosiee]

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Bug Category

Other

Describe the bug

If there is an error with parsing an entities or policy file a generic error is returned

`Err` value: EntitiesError("examples/simple/simple.entities.json")

This message contains no useful information other than the file path.

Examples of where this occurs

• https://github.com/cedar-policy/cedar-local-agent/blob/main/src/public/file/entity_provider.rs#L169
• https://github.com/cedar-policy/cedar-local-agent/blob/main/src/public/file/policy_set_provider.rs#L150

Expected behavior

The error from the cedar_policy should be included in the error message as it contains useful information such as serialization issues or schema errors.

https://docs.rs/cedar-policy/latest/cedar_policy/enum.EntitiesError.html

Reproduction steps

Create a entity provider with invalid entities.json file

Code Snippet

No response

Log output

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Additional configuration

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Operating System

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Additional information and screenshots

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